While N-heterocyclic diaminocarbenes (NHCs) have emerged as an important class of ligands in catalysis, their N,O-congeners, cyclic aminooxycarbenes (CAOCs) have not been frequently encountered as ancillary ligands despite having a different electronic profile. The structural variety of CAOCs is rather limited since both bonds of oxygen are incorporated in the heterocyclic core. Furthermore, CAOCs are less bulky than NHCs, because an oxygen lone pair in CAOCs does not exert the same level of steric protection as the flanking N substituents in NHCs. Considering that steric tuning of NHC ligands is often critical in the optimization process and that generally NHC ligands bearing bulky N substituents effectively promote a wide variety of reactions, the inherent lack of such possibilities could be a serious limitation in the potential development of CAOCs as useful ligands. Thus, there is a need to explore other options to overcome these deficiencies.